bolt/test/runtime/X86/shrinkwrapping-pushpop.s

   1 # This reproduces a bug with shrink wrapping when trying to move
   2 # push-pops where restores were not validated to be POPs (and could be
   3 # a regular load, which violated our assumptions). Check that we
   4 # identify those cases.
   5
   6 # REQUIRES: system-linux
   7
   8 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown \
   9 # RUN:   %s -o %t.o
  10 # RUN: link_fdata %s %t.o %t.fdata
  11 # Delete our BB symbols so BOLT doesn't mark them as entry points
  12 # RUN: llvm-strip --strip-unneeded %t.o
  13 # RUN: %clang %cflags -no-pie %t.o -o %t.exe -Wl,-q
  14
  15 # RUN: llvm-bolt %t.exe --relocs=1 --frame-opt=all --print-finalized \
  16 # RUN:    --print-only=main --data %t.fdata -o %t.out | FileCheck %s
  17
  18 # RUN: %t.out
  19
  20 # CHECK: BOLT-INFO: Shrink wrapping moved 1 spills inserting load/stores and 0 spills inserting push/pops
  21
  22   .text
  23   .globl  main
  24   .type main, %function
  25   .p2align  4
  26 main:
  27 # FDATA: 0 [unknown] 0 1 main 0 0 510
  28   pushq %rbp
  29   movq  %rsp, %rbp
  30   pushq %rbx                  # We save rbx here, but there is an
  31                               # opportunity to move it to .LBB2
  32   subq  $0x18, %rsp
  33   cmpl  $0x2, %edi
  34 .J1:
  35   jb    .BBend
  36 # FDATA: 1 main #.J1# 1 main #.BB2# 0 10
  37 # FDATA: 1 main #.J1# 1 main #.BBend# 0 500
  38 .BB2:
  39   movq $2, %rbx               # Use rbx in a cold block
  40   xorq %rax, %rax
  41   movb mystring, %al
  42   addq %rbx, %rax
  43   movb %al, mystring
  44   leaq mystring, %rdi
  45 # Avoid making the actual call here to allow push-pop mode to operate
  46 # without fear of an unknown function that may require aligned stack
  47 #  callq puts
  48
  49 .BBend:
  50   mov -0x08(%rbp), %rbx       # Original restore is here. Instead of a pop
  51                               # we use a load to reproduce gcc behavior while
  52                               # using leave in epilogue. Ordinarily it would
  53                               # addq $0x18, %rsp followed by pop %rbx
  54   xorq %rax, %rax
  55   leaveq
  56   retq
  57   .size main, .-main
  58
  59   .data
  60 mystring: .asciz "0 is rbx mod 10 contents in decimal\n"